The present invention is related generally to engine fluid heaters and more particularly to heaters for diesel internal combustion engine fuel. The present apparatus is especially useful for heating diesel fuel, though it can be used for heating other liquids such as lubricating oil, gasoline, or water.
Internal combustion engines (especially diesel engines) are notorious for being difficult to start in cold weather. Low temperatures cause difficulty in effective vaporization of fuel. Unvaporized fuel is difficult to ignite. Fuel that doesn't ignite collects in the engine cylinders and causes flooding.
At very cold temperatures, wax can congeal from diesel fuel within the fuel filter of a diesel engine. The congealed fuel and wax clogs the filter element and starves the engine of fuel. The engine will therefore die and refuse to start until the clogged fuel passage is cleared.
Condensation is another cold weather problem affecting both internal combustion fuel and lubricating oil. Water condensate in oil, gas, or diesel fuel causes further starting problems and promotes corrosion of the internal parts.
A recognized solution to the above problems has been to use various forms of water, oil, and fuel heaters. Special heaters are designed to operate independently from the engine, keeping the oil, water, or fuel at an elevated temperature while the engine is at rest. Such heaters are effective in some instances, but are often difficult to install. Such heaters tend to crowd the already overcrowded engine compartments. Many are too costly due to the special modifications that must be made for their proper installation on different makes and models of engines.
U.S. Pat. Nos. 3,083,833 and 3,097,165 to Kasten and 3,315,737 to Welch all disclose fuel heater and filter combinations wherein the heat exchanging element is in physical contact with the filter. The devices are supplied as units and fit in an aircraft engine fuel line and a coolant passage.
U.S. Pat. No. 2,721,544 to Kimberlin discloses an oil pump that circulates oil through a coil submerged within the heated water to warm the oil.
U.S. Pat. No. 2,713,422 shows the combination of a hot water filter arrangement with a conventional canister type oil filter. Water is directed through a filter arrangement and into a water jacket that surrounds the oil filter. Water warms the oil in the canister. This apparatus probably functions well for canister type filters but is restricted in its use to that particular type of filter.
U.S. Pat. No. 3,795,234 to Stolz discloses two water circulation systems for heating fuel. A pump-fitted heater operates thermostatically to preheat fuel, while a second system can operate with the first or separately therefrom to heat water.
U.S. Pat. No. 3,420,295 to Gotz discloses a combination of a heat exchanger and oil filter. The heat exchanger is situated within the same canister that holds the filter. It is not disclosed how the device is to be mounted to an engine. The device appears to completely replace an existing form of filter canister arrangement, thus requiring dismantling of the existing filtering system to allow installation. Additional modifications then must be made to connect the heat exchanger to the engine cooling system.
The fuel heater described herein can be mounted easily and quickly to an existing engine in close proximity to its fuel filter. The device mounts between the filter and filter mount. No special connections need to be made along the fuel line. The device can make use of heated water from the engine cooling system or an independent electrical heater, or both. The heater elevates the temperature of the incoming fuel and thereby prevents fuel and wax from congealing in the filter. Provision is also made for water separation.